This is a time when we can see game-changing musical mavericks of three generations share a stage, operating at the peak of their powers despite the disparity in their ages. These three artists have created their own personal vision of country music, freely combining it with whatever sounds they see fit — be it Nelson’s way with jazz and gospel or Musgraves’ folk-pop predilections — and forging new musical paths in the process.

Musgraves, who opened the evening, is only at the start of her journey, but with two Grammys and a No. 1 album already under her belt, she’s begun with a bang. Unsurprisingly, her set consisted mostly of tunes from her debut, Same Trailer Different Park, including her gold single “Merry Go ’Round”
and the anthemic “Follow Your Arrow.”

The exceptions included a smoky, sensuous new song called “High Time” and a Latin-tinged cover of George Strait’s 1998 chart-topper, “I Just Want to Dance With You.” Presumably, the Texan’s affection for the latter is due at least in part to the fact that it was co-penned by her hero, John Prine.

Musgraves was backed by a band whose look was somewhere between Outlaw country road dogs and old-school rhinestone-studded honky-tonk heroes, with a sound to match. For her part, she made the most of her bell-like tones and her knack for combining classic country influences with the melodic palette of the modern-day singer-songwriter she is.

And when she and her band members gathered together at the front of the stage for an a cappella version of the Roy Rogers chestnut “Happy Trails” at the end of the set, the musicians’ rhinestones lit up and started flashing on and off, showing that a sense of humor is part of Musgraves’ makeup, too.

Though the sweetness in Krauss’ sound precludes her ever being tagged anything as ornery as an “Outlaw,” she’s undeniably a musical maverick. After all, the girl who was turning Allman Brothers Band tunes into bluegrass before she was out of her teens eventually redefined the genre for a new era. The Radio City set shined a light on all the items in the toolkit she and Union Station employ.

Hearing the fiddler-singer and her faithful cohorts serve up everything from the down-home “Sawing on the Strings” to their transcendent cover of the Foundations’ ’60s soul hit “Baby Now That I’ve Found You” was like watching a flowchart for today’s newgrass nation, leading back to its own aesthetic foundations. The fleet fingers of virtuoso Jerry Douglas — the most celebrated musician ever to pick up a Dobro — fanned the flames ignited by Krauss’ fiddle, Dan Tyminski’s guitar and Ron Block’s banjo.

Tyminski’s delivery of two hits he sang outside the Union Station realm only reinforced the band’s broad appeal — one being “Man of Constant Sorrow,” the O Brother, Where Art Thou? soundtrack sensation he voiced for George Clooney, and the other 2013’s worldwide dance-pop hit “Hey Brother”
by Swedish electronic artist Avicii, which featured the bluegrass stalwart’s lead vocal. The band wisely elected to leave the dance beats out of the arrangement on the latter.

Of course when it comes to country nonconformists, Nelson not only wrote the book, he published it and put it on the shelves. Country’s original Outlaw has spent decades proving it’s possible to be an icon and an iconoclast at the same time. A week before the release of his 69th (!) studio album, Band of Brothers, Nelson and his close-knit band the Family found time for just one tune (the title track) from that record, but when you’re a living legend there are a lot of songs you need to play if you want to leave the stage with your hide intact.

His set included all the hits you’d hope for, from Outlaw-era evergreens (“Good Hearted Woman,” “Mammas Don’t Let Your Babies Grow Up to Be Cowboys”) to pop crossover smashes (“On the Road Again,” “Always on My Mind”) and the early Nelson-penned tunes that became hit singles for Patsy Cline (“Crazy”), Ray Price (“Night Life”), and Billy Walker (“Funny How Time Slips Away”). Along the way he threw in everything from Billy Joe Shaver’s churning “Georgia on a Fast Train” to Tom T. Hall’s “Shoeshine Man.”

Nelson has always had a jazzman’s approach to phrasing, partly inspired by his hero Lefty Frizzell, but he has refined and deepened his delivery. Whether he’s singing “Beer for My Horses”
or crooning Hoagy Carmichael’s “Georgia on My Mind,” Nelson plays with the tunes’ timing like a cunning cat toying with a particularly appetizing mouse. He’ll sing in front of, behind or in and around the beat as the moment suits him, always choosing his phrasing for the maximum impact in the moment.

His guitar style, a musical mongrel mixing country, jazz, and Mexican folk, is equally elastic, allowing his trenchant licks plenty of elbow room. He still sports the same battered Martin axe, “Trigger,” that he’s been playing exclusively since 1969.

Watching Nelson work his magic as he did at Radio City is a thrilling experience in and of itself, but the push and pull between his adventurous excursions and the no-nonsense, rock-solid beat of the Family creates an almost giddy kind of contrast, as if Nelson was venturing ever further on a high wire without losing his footing.

He finally brought out Krauss, Musgraves and their musicians for a foot-stomping, hand-clapping, gospel ending to the evening, delivering “Will the Circle Be Unbroken,” “I’ll Fly Away,” Nelson’s own stoners’ prayer “Roll Me Up and Smoke Me When I Die” and Hank Williams’ “I Saw the Light.” With all hands on deck dishing out the licks and lyrics, the octogenarian icon still couldn’t resist slipping and sliding around the tunes, goosing the God-fearing finale with irreverence worthy of an authentic Outlaw.